An electrochemical system for the rapid and accurate quantitation of microbial exoelectrogenic ability

Microbial extracellular electron transfer (EET) plays a vital role in globally important environmental phenomena, including bioremediation, bioenergy generation, and biofuel production. The quantitation of microbial exoe-lectrogenic ability is fundamental to studying the process of EET. However, there is no accurate and time-saving protocol to directly evaluate EET ability, hindering our understanding and application of EET. In this work, we proposed an accurate and rapid quantitation system for measuring EET ability using a gold-coated membrane filter as a working electrode. The quantitation signals could be recorded within 1 h and accurately normalized by the number of cells with outstanding repeatability and reproducibility. Further, this method could be distin-guished microbial direct EET performances of different growth stages, and the results showed the middle log-arithmic growth stage of Shewanella onedensis MR-1 had the best electrochemical activity. This method can be widely used for different types of electroactive microorganisms, including gram-negative bacteria, gram-positive bacteria, and fungi. Due to its time savings, accurate quantification and easy operation, this method provides a standard way to assess the role of EET ability.

Automated summary

Microbial extracellular electron transfer plays a crucial role in environmental processes, but there is currently no accurate and time-saving method to evaluate this ability. This study proposes a fast and precise quantitation system for measuring microbial extracellular electron transfer using a gold-coated membrane filter as a working electrode, which can be applied to different types of microorganisms.